class_docstr: A memoizing mapping that retains `capacity` deleted items
  
  The memo tracks retained items by their access order; once `capacity` items
  are retained, the least recently used item is discarded.
code: def __delitem__(self, key):
      try:
          value = self._active.pop(key)
      except KeyError:
          pass
      else:
          while len(self._memory) >= self._capacity:
              self._memory.popitem(last=False)
          self._memory[key] = value
  
imports: import inspect
  import warnings
  import types
  import collections
  import itertools
  from functools import lru_cache, wraps
  from typing import Callable, List, Union, Iterable, TypeVar, cast
label_desc: Use image node_id 4 for calling the LRUMemo obj's underlying member method code with example usage: obj.__delitem__(key) without return types